Q. What is true about RBCs in humans?
A) They do not carry CO₂ at all
B) They carry about 20-25 percent of CO₂
C) They transport 99.5 percent of O₂
D) They transport about 80 percent oxygen only and the rest 20 percent of it is transported in dissolved state in blood plasma
Explanation
[Solution from source] About 20–25% of CO₂ is carried by RBCs as carbamino-haemoglobin, about 70% as bicarbonate, and about 7% dissolved in plasma. For oxygen, about 97% travels bound to haemoglobin in RBCs and 3% dissolved, so the 99.5% and 80% figures are wrong. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.